Launch vehicles can use pressure fed cycle in any stage of the rocket, but here i am interested for those vehicles which used this cycle in all stages. What is the current record in terms of mass of payload delivered to LEO for such vehicles? I don't count suborbital flights and vehicle must be launched from Earth. Also i don't count conceptual vehicles, only one which successfully delivered payload in LEO.
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$\begingroup$ Can you give an example of such a vehicle? In other words, have there been any? $\endgroup$– Organic MarbleNov 21, 2020 at 15:44
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$\begingroup$ I am not sure, that's why i am asking. If correct that none of pressure fed vehicles reached LEO than 0kg is acceptable answer. I know for never flown concepts but thats not the point of question. $\endgroup$– WOW 6EQUJ5Nov 21, 2020 at 16:29
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1$\begingroup$ Disqualified for your question, but OTRAG and Sea Dragon were intended to launch to orbit on pressure fed engines. OTRAG never flew to orbit and Sea Dragon (which certainly would have had the payload record) was never built. $\endgroup$– Russell BorogoveNov 21, 2020 at 18:15
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$\begingroup$ Was going to mention OTRAG, but Russell beat me to it. It got to at least 150 km altitude, but not to orbital speed. It was designed to carry 2 tons all the way to geostationary orbit. $\endgroup$– DrSheldonNov 21, 2020 at 19:25
1 Answer
AFAIK it is "0.0 kg".
Orbital launch vehicles with pressure-fed first stages are few and far between. Diamant had that with its Vexin engine, but solid upper stage.
I don't know of any successful orbital vehicle with all pressure-fed stages, but maybe there's an obscure one out there.
See also Some examples of pressure fed engines used on launch vehicles